Plug fuse



May 19, 1936.

R. W. KING PLUG FUSEY 2 Sheets-Sheet 1 Filed Aug. 51, 1935 1 r I r r I 3 I I A I I 1 1 3 a 1/ I QQ v3 I \O Patented May 19, 1936 UNITED STATES PATENT OFFICE 6 Claims.

This invention relates to fuses for electrical circuits, and more particularly to the type known as a plug fuse, and the invention aims to provide an improved plug fuse having, among others, the

novel features herein described and claimed.

In the drawings illustrating one embodiment of my invention selected for illustration and description herein:-

Fig. 1 is a plan, or upper end view;

Fig. 2 is a vertical section on the line 2-2 of Fig. 1, looking in the direction of the arrow;

Fig. 3, a similar view showing the fuse as blown, and certain parts in different and inoperative positions;

.Fig. 4, a vertical section on the line 4-4, Fig. 1, looking in the direction of the arrow;

' Fig. 5, an end View of the fuse element;

- Fig. 6, a face, or side view of the fuse element; Fig. 7, an edge view of the same; and

Fig. 8, a diagrammatic View of the inner wall of the body member and showing the slot forming the path of travel of the magazine positioning and fuse renewing pin.

Referring first to Figs. 1, 2, 3, my novel plug fuse comprises a curvilinear cap member I, of suitable non-conducting material, as porcelain, with a depending central, tubular portion 2, the bore of which extends through the cap and having a ring-like flange 3 on the tubular portion. The upper face of the cap is countersunk about the edge of the bore to receive a button stop ring 4 of suitable material, as metal.

This cap member, Fig. 2, overlies a similarly shaped shell-like body member or housing 6 of similar or other suitable material, with inwardly extended rings or flanges I, 8, the former abutting a similarly shaped ring 3, on the member I, and the latter abutting a like ring 9 on the plug portion II] of the plug to be described. This member 6 is made of two semi-circular members having dovetailed, vertical interlocking edges, see dotted lines Fig. 1, which members are separable, as will be described later.

' The cap I and the flange II of the member I0 are secured to each other at a fixed distance apart by two bolts 36, Fig. 4, having nuts 31 on each end, which permit the two halves of the body to be separated at will. The members 2 and ID are each locked against lateral movement relative to the member 6 by screws I 9.

The member I0, Figs. 2, 3, is flanged at its upper end as at II, to receive the screws I 9, and threaded at its lower end I2, for locking contact with the usual socket, not shown, which is part of the conventional electric installation.

The cap I, Figs. 2, 3, is grooved circumferentially, on its lower face to receive, when molded, a conductor ring 2I of suitable material, as chromium-plated copper, and this ring is, in turn, slotted laterally to receive at circumferentially spaced points thereon the inturned ends of fuse members 22, the lower inturned ends of which are likewise received in the upper end of the member I0, which is slotted for that purpose, the several members thus constituting a magazine for the fuses. These fuses are firmly held in position by the abutting flanges 3, I, at the upper ends, and the flanges 8, 9, at the lower ends.

The member I, Figs. 1, 2, 3, carries on its inner face a series of vertical, inwardly extended ribs 24, positioned each between two fuses to isolate them and assist in preventing the creation of an are between any two fuses at any time that either of them may blow. The screw-threaded end I2 of the member ID is covered with the usual threaded conductor sleeve 25. At its lower end, the member In is provided with a conductor in the form of a socket or eyelet 26, into which is threaded a conductor screw 21, to engage a conductor member in the bottom or inner end of the usual socket therefor, not shown.

The member 26 is provided on its inner end with a ball-shaped support 28, received in the lower end of a hollow plunger housing 29, to form a suitable thrust bearing therefor, as will be described. The lower end of the member 29 is split vertically two or three times, dotted lines Figs. 2, 3, and the several portions separated slightly and sprung over the ball 28 in assembling, and then compressed together.

At one point, Fig. 2, the side wall of the housing 29 is cut away to receive the curved end 30 of a goose-neck conductor member 3|, the lower end of which is secured to the housing wall, while the upper end is normally in contact with one of the fuses 22.

Within and on the bottom of the housing 29 is seated a housing rotating coiled spring 32, upon which is seated the lower end of a metallic plunger 33. This plunger also is slotted longitudinally 4 as at 34, to receive the conductor 3|, and the slot so positioned and proportioned that, when the plunger is restrained, as in Fig. 2, the curved goose-neck 3I is forced by its bearing against the slot horizontal edge of the plunger in contact with a fuse 22, and thus acts as a detent for the plunger to hold it in operative position.

The upper end of the plunger 33, Fig. 2, carries upon it a button 35, the upper end of the button projecting normally slightlyfrom the ring 4. To

look the parts I, H), as described, together, the bolts 36 are used, and one bolt, Fig. 4, is used as a conductor in the electric circuit through the plug. The upper end of bolt 36, Fig. 4, contacts with a conductor plate 38 in the cap I, which plate is in contact with the conductor ring 2|, while the lower bolt end engages one end of a conductor strip 39 on the member ID, the lower end of the strip contacting the threaded sleeve 25 on the member l0.

Thus, it will be evident that when the plug is screwed into the usual socket in the installation, a circuit for the current is established from the inner wall of the socket through the sleeve 25, strip 39, bolt 36, plate 38, contact ring 2|, fuse 22, member 3|, housing 29, bearing 28 and socket member 21, to the opposite circuit terminal in the socket, the above circuit being broken by the blowing of the fuse.

The housing 253 has projecting from its outer wall a. semi-circular ring 40, to center the housing in the member l6, and to reduce the friction between the housing 29 and the inner wall of the plug section [0.

The inner wall of the plug section 10 of the plug, Fig. 8, is provided with an irrgularly shaped housing-rotating groove 44 of suitable dimensions and angles to receive the end of a housing-feeding pin 42 projecting from the side of the plunger 33 through a slot 43 in the housing. At one point, this groove is provided with a straight section 44, which permits the introduction of the plunger and housing into the member It! when assembling.

The normal position of the pin 42 is shown at Fig. 2. When a fuse blows, the member 31 is pushed by the plunger, actuated by the spring 32, outwardly against the ruptured fuse, Fig. 3, to separate the ends and offset any tendency of the current to are from one end to the other end of the ruptured fuse, and the plunger 33 is thrust upward, causing the push button 35 to be ejected as shown in Fig. 3, thus distinctly pointing out the particular plug containing the fuse that has blown.

When this plug fuse is used in a battery or series of plugs, it is a great advantage to be able to ascertain at once, without testing, which one contains the disrupted fuse. When the fuse blows, the pin 42 on the plunger travels angularly and upwardly to dotted line position, Fig. 8, and as shown, Fig. 3. The plug is then quickly again restored to service by pressing with the finger the button 35 back into position. When the button is pushed downwardly or inwardly into the housing, the pin 42 moves angularly and downwardly in the angular section 4| of the groove, to a dotted line position, 45, corresponding to its original position, as shown in Fig. 8, in the adjacent lower point of the groove, the travel of the pin in the groove at the same time rotating the housing sufficiently to operatively position it opposite the adjoining fuse. The member 30 has sufficient natural resiliency to cause it to swing inwardly as in Fig. 2, when the lower portion of the plunger 33 is out of the path of movement of the member 3 I, and it then rests under pressure of the plunger against the new fuse in operative position, as before.

In this manner, the plug fuse may be instantly restored to service, without delay and removal, until all the fuses have been used up. When the next fuse blows, it will release the detent 3:3 and, as the plunger moves upwardly, the pin 42 will travel in the upwardly and angularly extended section of the groove 4|.

For convenience while reinserting new fuses after the original have all been blown, the cap I is provided with a plunger retaining plate 46 pivoted to the cap I and swingable over the button 35, to force the same inwardly and lock it therein, so as to permit the member 30 to move into the slot in the housing and the new fuses to be inserted.

There is thus provided a novel plug fuse with a magazine that may readily be replenished with fuses by simply removing the member 6 from the assembly. All the moving parts except the plate 46, are enclosed and protected.

My invention is not restricted to the particular embodiment thereof herein disclosed and described.

I claim:

1. A plug fuse comprising a plug section, conductor members thereon, a magazine body, a fuse therein, a plunger also therein, a means for ejecting the plunger, and a plunger detent mounted without the plunger and held by the plunger against the fuse, and thereby wedged between said fuse and plunger to restrain the latter and releasable by the fuse when blown, and a blown fuse plug indicating member projectable by the released plunger.

2. A plug fuse comprising a plug section, conductor members thereon, a magazine body, a plurality of fuses therein, a housing with a plunger also thereinra spring for ejecting the plunger, a plunger detent mounted without the plunger and held by the plunger in contact with the fuse, and thereby acting as a wedge between the fuse and plunger to restrain the latter, the detent releas' able by the fuse when blown, a. track on the wall of the body, a pin carried by the plunger and positioned in said track; a blown fuse plug indicating button in the housing and projectable by the plunger when released by the blown fuse, and operable with the pin and track when pushed inwardly to position in the housing to cause the housing to rotate to operatively position a second fuse.

3. A plug fuse comprising a plug section, conductor elements thereon, a body, a plurality of fuses therein, a housing therein with a plunger and a housing positioning track, a spring for ejecting the plunger, a plunger detent carried by and extended through the housing and forced by the plunger against the fuse to hold the plunger in operative position, and releasable by a blown fuse, and a track on the body wall, a housing positioning pin in the plunger and engaging the housing and track; a blown fuse plug identifying member operable by the plunger to identify the location of the blown fuse and operable with the plunger and track to position the housing operably relative to the plunger and a second fuse.

4. A plug fuse comprising a plug section, conductor elements thereon, a body with a plurality of circuit conductors therein, a plurality of fuses mounted in the plug, a conductor-detent-carrying housing automatically rotatable in the body and normally positioning the detent relative to the fuse to create a circuit with the housing conductor when the plunger is pushed inwardly; a plunger within the housing and a spring therefor controlling the positionjof said detent, and a blown-fuse plug identifying member actuated by the plunger when the fuse blows to identify the plug, and actuated with the plunger to reposition the plunger and housing relative to the fuses to cause the conductor detent to contact a second fuse in said plug circuit.

5. A plug fuse comprising a plug section, conductor elements thereon, a cap section secured thereto, a magazine body section with a plurality of circuit conductors therein, the body section removable from the cap and plug sections to permit renewal of the fuse elements, a plurality of fuses mounted in the plug, a conductor-detentcarrying housing rotatable in the body and normally positioning the detent relative to the fuse to create a circuit with the housing conductor when the plunger is pushed inwardly; a plunger within the housing and a spring therefor controlling the position of said detent, and a blown-fuse plug identifying member actuated by the plunger when the fuse blows to identify the plug, and actuated with the plunger to reposition the plunger and housing relative to the fuses to cause the conductor detent to contact a second fuse in said plug circuit.

6. A plug fuse comprising a plug member with conductor elements therein including a conductor ring and plate in the plug, fuses in the member and fuse isolating members therein, a rotatable housing therein carrying a detent normally in contact with a fuse; a plunger in the housing slotted to receive said detent and acting to wedge the same against the fuse; a housing and detent positioning track on the plug member and a track engaging member on the plunger and extended through the housing; a plug-identifying member operable by the plunger to identify the blown-fuse-carrying plug when the fuse blows and the detent is released; said identifying member operable with the track and track-engaging member to automatically reposition the plunger relative to a new fuse; and a plunger retaining plate to hold the plunger in normal position while renewing fuses.

REGINALD W. KING. 

